Combination lock



July 18, 196 R. w. ARMSTRONG COMBINATION LOCK Filed April 23, 1965 Fla.l

92m ART I N VENTOR ATTOR NE Y United States Patent 3,331,228 COMBINATIONLOCK Richard W. Armstrong, Rockville, Md., assignor to the United Statesof America as represented by the Secretary of the Army Filed Apr. 23,1965, Ser. No. 450,551 Claims. (Cl. 70-303) ABSTRACT OF THE DISCLOSUREThis invention relates to an improved combination lock having a springbiasing means for axially moving a drivershutter assembly out ofengagement with a detent to eliminate noise, drag and wear during normalcombination dialing associated with a combination lock similar to theone described in US. Patent No. 3,073,145, issued January 15, 1963, toAnthony J. Potzick.

This invention may be manufactured and used by or for the Government forgovernmental purposes without the payment to me of any royalty thereon.

This invention relates to a combination lock and more particularly to animprovement in an uncontrolled-motion, manipulation-resistant lock. Theinvention is related to and constitutes an improvement over theinvention disclosed in United States Patent No. 3,073,145. Theimprovement is concerned with eliminating the rather loud noise androtational drag produced when the combination of the Potzick lock isdialed. By means of this improvement, the Potzick lock will operate moresmoothly and quietly and with reduced wear.

The noise and rotational drag associated with the Potzick lock arecaused by an uncontrolled-motion shutter which is attached to the wheeldriver to prevent the angle bar nose from engaging the edges of thedriver notch. The shutter is provided with detent notches which coactwith a detent mechanism to operate the shutter. A detailed statement ofthe structure and operation of the shutter mechanism and its use inpreventing manipulation to determine the location of the wheel gates iscontained in US. Patent No. 3,073,145. The improvement of this inventionconsists in axially moving the driver-shutter assembly out of verticalalignment with the detent mechanism during the combination dialingoperation, thus eliminating the detent noise, drag and wear. After acombination is dialed, the drivershutter assembly is returned tovertical alignment with the detent and the dial is turned to engage theangle bar and withdraw the lock bolt. It is only after a combination isdialed and while the dial is being turned to engage the angle bar thatthe shutter mechanism is required to prevent manipulation.

An object of the invention is to provide an uncontrolled motion,manipulation-resistant lock, the combination of which can be dialedsmoothly and noiselessly without lessening the security of the lock.

Another object is to provide a combination lock whose driver-shutterassembly can be moved axially in or out of vertical alignment with ananti-manipulation detent mechanism so that the detent mechanism is notoperated except when the lock fence tests whether the wheel gates havebeen properly aligned.

Another object is to lessen the wear on the drivershutter-detentmechanism of an uncontrolled-motion, manipulation-resistant lock.

The structural features of the invention are illustrated in theaccompanying drawings in which:

FIG. 1 is a top view of a combination lock of the type to which thisinvention relates;

3,331,228 Patented July 18, 1967 ice FIG. 2 is a cross-sectional view ofa preferred drivershutter-detent assembly taken on line 2-2 of FIG. 1;

FIG. 3 is an elevation view, partly broken away, of the assembly shownin FIG. 2, the wheels, gates, fence and angle bar nose being shown inphantom; and

FIG. 4 is a side view, partly broken away, of the assembly shown in FIG.3.

Referring to the drawings, FIG. 1 generally illustrates the combinationlock 1 to which this invention relates. The lock is shown mounted to asafe door 2. Lock 1 comprises a rotatable dial 3, and an index 4 locatedon the outside of door 2. Secured to the inside of door 2 is case 5containing lock mechanism 6. Case 5 has a removable back portion 7. Lockbolt 8 is shown extending through case 5 for engagement with a boltreceiving member in the body of the safe, not shown.

Referring to FIG. 2, the lock mechanism comprises a shaft 9, a spring10, a shutter 11, a driver 12, a plurality of wheels 13 and a detent 14.Shaft 9 is fastened to and rotatable with dial 3 and it extends throughdoor 2 and case 5 to operate lock mechanism 6. Driver 12 is secured toshaft 9 by a key 15 having a pair of spaced legs 16 which are receivedin diametrically spaced grooves 17 and 18 (FIG. 3) formed in shaft 9 andhub 19 of driver 12, respectively. Hub 19 extends on both sides ofdriver 12. Drive pin 20 extends from the inner face of driver 12 toengage the first of a plurality of wheels 13.

Shutter 11 is rotatably mounted on hub 19 and is held in place by springclip 21. Shutter 11 has a central hub 22 and a peripheral rim 23 whichextends on both sides of the central disk 24. Rim 23 and hub 22 areclosely adjacent driver 12 and together with driver 12 and disk 24define a cavity within shutter 11. A torsion spring 25 intercouplesshutter 11 and driver 12. Spring 25 fits around hub 22 and is hookedaround spring pins 26 and 27 located on driver 12 and shutter 11,respectively (FIG. 4). Pins 28 and 29 on shutter 11 are slightly longerthan pin 26 and serve as stops to limit the rotation of shutter 11 withrespect to driver 12. The functioning of pins 28 and 29 is more fullydescribed in US. Patent No. 3,073,145. Detent notches 30, 31 and 32 areformed in the inner periphery of rim 23, that is, on the side nearestdriver 12. Rim 23 forms a smooth and continuous band around shutter 11on the side nearest spring 10.

Detent 14, made up of housing 33, spring 34, plate 35 and ball 36, is ofthe same structure as the detent shown in United States Patent No.3,073,145. Likewise, the configurations of driver 12, shutter 11, wheels13, angle bar nose 37 and fence 38 are essentially the same as thosestructures shown in Patent No. 3,073,145 and the functions of thesestructures are explained in detail in that patent. There are severalimportant structural differences between this invention and theinvention disclosed in Patent No. 3,073,145, however, and thesedifferences will now be described in detail.

Shutter 11 has been modified by extending rim 23 past disk 24 on theside of shutter 11 facing spring 10. Spring 10 has been added to thePotzick lock between case 5 and shutter 11 to force the driver-shutterassembly out of vertical alignment with detent 14 during normalcombination dialing. Shaft 9 is also forced inwardly by the action ofspring 10. Rim 23, as extended, forms a smooth continuous surface uponwhich angle bar nose 37 rides when the driver-shutter assembly isrotated in the normal position, which is out of alignment with detent14. The drivershutter assembly can be moved axially into alignment withdetent 14 by pulling dial 3 out against spring 10.

To maintain the increased security described in Patent No. 3,073,145,however, the driver-shutter assembly must not be pulled toward case 5when the dial setting is within approximately 10 degrees of either sideof zero. In this area, pulling the driver-shutter toward case wouldallow manipulative readings to be made as the dial is rotated and anglebar nose 37 dips toward the notch of driver 12. To avoid this securityproblem, sector 39 has been added to driver 12. Sector 39 overrides stop40 during an increment of rotation of approximately degrees. Stop 40extends from case 5 and is so located that sector 39 overrides the stopduring the increment of dial rotation which extends approximately 10degrees on either side of the zero setting. These settings reflect theincrement of rotation during which the driver notch is rotationallyaligned under angle bar nose 37. The extension of rim 23, and theaddition of spring 10, sector 39 and stop 40 constitute the essentialstructural changes over the Potzick lock.

In operation, the combination of the lock is dialed with thedriver-shutter assembly in its normal position, out of verticalalignment with detent 14. Assuming the combination to be the 3-numbercombination, 50-30, the operator would dial the combination with thedriver-shutter in normal position. During this dialing, detent notches30, 31 and 32 would not come in contact with detent 14 and the dialwould turn quietly, without rotational drag and with no wear on eitherthe detent or the detent notches. After the combination is dialed, thedial must be returned from to zero so that fence 38 can drop into thegates of wheels 13 and angle bar nose 37 can drop into the driver notch.The operation of returning from 30" to zero is performed with thedriver-shutter in vertical alignment with detent 14 and with the drivernotch in vertical alignment with angle bar nose 37. The alignment isbrought about by the operators pulling out on dial 3 thereby compressingspring 10. Detent 14 is engaged during this return. At the zero setting,angle bar nose 37 drops into the driver notch and, upon further rotationof the driver, the angle bar, which is attached to the lock bolt, movesto withdraw the bolt into case 5, the sector 39 preventing thedriver-shutter from returning to its normal position during an incrementof dial movement of approximately 10 degrees on either side of zero.

By the improvement of this invention, the Potzick lock and similar typelocks can be made to operate quietly and without rotational drag ordetent wear. At the same time, there is no diminishing of the securityof the Potzick lock since the detent is engaged during the crucialperiod of the return to zero at the end of the combination dialing andsince stop 40 prevents a rotational and vertical align ment of angle barnose 37 and the driver notch without detent contact.

I claim:

1. In a combination lock having a rotatable dial, a shaft rigidlyconnected to said dial, a plurality of rotatable wheels, a driverrigidly connected to said shaft for engaging one of said wheels, ashutter interconnected to and rotatable with and with respect to saiddriver and having detent notches along a portion of its periphery, anangle bar having a nose which is supported by the periphery of saidshutter throughout a portion of each revolution of said shutter and adetent which is in alignment with and which engages and disengages withthe detent notches of said shutter as the shutter rotates, saidengagement and disengagement imparting a motion to said shutter which isnot controllable by the lock operator, the improvement which comprises:

(a) means for axially moving the shutter a sufficient distance todisalign the detent notches of said shutter and said detent duringnormal combination dialing, said means allowing the detent notches ofsaid shutter to be moved into alignment with said detent during aportion of the combination dialing operation, including the finalopening operation; and

(b) means for continuously supporting the nose of said angle bar duringrotation of said shutter when said shutter is disaligncd with saiddetent.

2. The combination lock improvement described in claim 1 wherein saidmeans for moving said shutter is a resilient means and wherein saidmeans for continuously supporting the nose of said angle bar comprises asmooth continuous rim attached to said shutter.

3. The combination lock described in claim 1 wherein said improvementfurther comprises means for preventing the axial movement of saidshutter during a portion of the rotation of the combination dial.

4. The combination lock improvement described in claim 3 wherein saidmeans for preventing axial movement of said shutter during a portion ofthe rotation of the combination dial comprises a sector attached to saiddriver and a stop attached to the lock frame, said sector and stop beingso located that the sector overrides the stop during a portion of thedial rotation to prevent movement of said driver and shutter relative tosaid stop.

5. The combination lock improvement described in claim 4 wherein saidsector and said stop are located so as to prevent axial movement of saidshutter during approximately 20 degrees of rotation, said 20 degreesbeing the 10 degrees on either side of the zero setting of thecombination dial.

References Cited UNITED STATES PATENTS BOBBY R. GAY, Primary Examiner.

1. IN A COMBINATION LOCK HAVING A ROTATABLE DIAL, A SHAFT RIGIDLYCONNECTED TO SAID DIAL, A PLURALITY OF ROTATABLE WHEELS, A DRIVERRIGIDLY CONNECTED TO SAID SHAFT FOR ENGAGING ONE OF SAID WHEELS, ASHUTTER INTERCONNECTED TO AND ROTATABLE WITH AND WITH RESPECT TO SAIDDRIVER AND HAVING DETENT NOTCHES ALONG A PORTION OF ITS PERIPHERY, ANANGLE BAR HAVING A NOSE WHICH IS SUPPORTED BY THE PERIPHERY OF SAIDSHUTTER THROUGHOUT A PORTION OF EACH REVOLUTION OF SAID SHUTTER AND ADETENT WHICH IS IN ALIGNMENT WITH AND WHICH ENGAGES AND DISENGAGES WITHTHE DETENT NOTCHES OF SAID SHUTTER AS THE SHUTTER ROTATES, SAIDENGAGEMENT AND DISENGAGEMENT IMPARTING A MOTION OF SAID SHUTTER WHICH ISNOT CONTROLLABLE BY THE LOCK OPERATOR, THE IMPROVEMENT WHICH COMPRISES:(A) MEANS FOR AXIALLY MOVING THE SHUTTER A SUFFICIENT DISTANCE TODISALIGN THE DETENT NOTCHES OF SAID SHUTTER AND SAID DETENT DURINGNORMAL COMBINATIOIN DIALING, SAID MEANS ALLOWING THE DETENT NOTCHES OFSAID SHUTTER TO BE MOVED INTO ALIGNMENT WITH SAID DETENT DURING APORTION OF THE COMBINATION DIALING OPERATION, INCLUDING THE FINALOPENING OPERATION; AND (B) MEANS FOR CONTINUOUSLY SUPPORTING THE NOSE OFSAID ANGLE BAR DURING ROTATION OF SAID SHUTTER WHEN SAID SHUTTER ISDISALIGNED WITH SAID DETENT.